VI Editor Basics - 1

Introduction

The VI editor is a screen-based editor used by many Unix users. The VI editor has powerful features to aid programmers, but many beginning users avoid using VI because the different features overwhelm them.

Starting the VI Editor

The VI editor lets a user create new files or edit existing files. The command to start the VI editor is vi, followed by the filename. For example to edit a file called temporary, you would type vi temporary and then return. You can start VI without a filename, but when you want to save your work, you will have to tell VI which filename to save it into later.
When you start VI for the first time, you will see a screen filled with tildes (A tilde looks like this: ~) on the left side of the screen. Any blank lines beyond the end of the file are shown this way. At the bottom of your screen, the filename should be shown, if you specified an existing file, and the size of the file will be shown as well, like this:

"filename" 21 lines, 385 characters

If the file you specified does not exist, then it will tell you that it is a new file, like this:

"newfile" [New file]

If you started VI without a filename, the bottom line of the screen will just be blank when VI starts. If the screen does not show you these expected results, your terminal type may be set wrong. Just type :q and return to get out of VI, and fix your terminal type. If you don't know how, ask a lab monitor.

Getting Out of VI

Now that you know how to get into VI, it would be a good idea to know how to get out of it. The VI editor has two modes and in order to get out of VI, you have to be in command mode. Hit the key labeled "Escape" or "Esc" (If your terminal does not have such a key, then try ^[, or control-[.) to get into command mode. If you were already in the command mode when you hit "Escape", don't worry. It might beep, but you will still be in the command mode.

The command to quit out of VI is :q. Once in command mode, type colon, and 'q', followed by return. If your file has been modified in any way, the editor will warn you of this, and not let you quit. To ignore this message, the command to quit out of VI without saving is :q!. This lets you exit VI without saving any of the changes.

Of course, normally in an editor, you would want to save the changes you have made. The command to save the contents of the editor is :w. You can combine the above command with the quit command, or :wq. You can specify a different file name to save to by specifying the name after the :w. For example, if you wanted to save the file you were working as another filename called filename2, you would type: w filename2 and return.